1. Field of the Invention
A first aspect of the present invention relates to a smoke supervisory system, and more particularly relates to a smoke supervisory system constantly supervising an installation, equipment, or the like, existing on a large scale e.g., an outdoor space, which immediately detects the generation of smoke as a result of a fire, and activates an alarm or the like.
A second aspect of the present invention relates to an equipment supervisory system, and more particularly to an equipment supervisory system constantly supervising the temperature of equipment installed in an arbitrary space and outputting alarm information on the detection of an abnormal temperature.
2. Description of the Related Art
Generally when a fire occurs in large scale equipment, apparatuses, or the like installed in a large space e.g., indoor or outdoor, and if fire fighting is carried out, the possibility of loss of life and valuable resources or equipment is high. Therefore, it is necessary to accurately detect and measure the generation of smoke by supervising the same in order to prevent the fire.
The generation of smoke is as follows. First, when a small temperature change occurs locally, an abnormal temperature domain spreads rapidly and when the stored heat in the equipment attains an ignition point, a fire or explosion occurs.
At that time, sudden ignition from the normal state does not occur, and as a middle step, preliminary smoke generation is started. Accordingly, the smoke supervisory system is necessary. As a supervisory system for detecting smoke generation, a sensor using system and a visible ray camera system has been proposed.
The sensor system widely uses a smoke sensor e.g., semiconductor gas sensor utilizing an oxide semiconductor to detect smoke generation directly from the equipment or apparatus installed in an arbitrary space indoors. In the smoke supervisory system utilizing a smoke sensor, the sensor is attached on the ceiling indoors, responds and detects the smoke or gas generated from various equipment or apparatuses installed locally by an oxide reaction in the sensor, transmits the detected data to separate installed supervisory equipment and monitor, and when the density of the smoke or gas attains a certain value, an alarm is activated.
In a visible camera system, a common television camera is used that displays an arbitrary space indoors as a visible image. In this system, an operator constantly monitors the image, detects an abnormal image due to smoke generating from the equipment installed in the said space, and outputs an abnormal display or alarm by manual operation.
In the conventional system using the smoke sensor, since it is a spot sensor, and the density of the smoke or gas generated from the equipment is detected locally, it is unsuitable for a plurality of equipment or for the supervision of a large space outdoors. Further when in a large indoor space, it takes a long time for the spot sensor to detect gas or smoke emanation. As a result, only in small spaces and under limited conditions, can the rapid detection of smoke or gas generation be carried out. In addition since the operator directly monitors the area, and the detection of smoke is not automatic, a misoperation due to human error can occur.
While recently, in electric power plants having large transformers or the like and in petrochemical plants, an equipment supervisory system that can monitor the temperature conditions or provide inspection time information constantly and accurately is desired to prevent a fire or explosion, and to ensure the efficient maintenance and conservation of power.
In a conventional equipment supervisory system, in order to detect an abnormal temperature generated in equipment installed in a space outdoors or indoors, thermocouples, thermisters, or the like, which are contact type temperature sensors, are utilized.
In the equipment supervisory system utilizing temperature sensors, the sensors are fixed on the equipment, the detected temperature data is transmitted to the supervisory apparatus and monitored. When an abnormally high temperature is detected, an abnormal display or alarm is output or activated.
Since contact type sensors are point sensor types, however, many sensors are necessary when a plurality of equipment exist or a plurality of portions require monitoring. Further when an abnormally high temperature is detected, it is occasionally only just before a fire or explosion, and consequently is too late. Therefore with this type of sensor, the early detection of an abnormal temperature is difficult.
On the other hand, instead of using temperature sensors as an equipment supervisory system detecting the early occurrence of an abnormal temperature of large scale equipment covering a large area, a method utilizing a differential temperature image is proposed.
In this method, the temperature of the said equipment is monitored by an infrared ray camera, and two different infrared images, separate in time, are stored as an input image and a reference image, and a simple differential image between the two images is obtained. The differential image is displayed as a histogram to the temperature and image element number by graphical representation; they are compared with predetermined detecting temperature data and a detecting image element number, and when they are in excess, an abnormal temperature is detected early and an alarm or display of the abnormal temperature sign is output.
In the equipment supervisory system utilizing the differential infrared image, in contrast to the point temperature sensor, a multipoint inspection wherein multiple temperature data can be obtained simultaneously, and, if the object equipment exist outdoors, abnormal temperature indication caused by the effect of sunshine, wind, or change of environmental temperature is not detected.
The conventional arts regarding this invention, are disclosed in Japanese unexamined patent publications (Kokai) 1-288086, 2-109196, and 3-182185.